NAME

SYNOPSIS

DESCRIPTION

The <sys/msg.h> header shall define the following data types through typedef:

msgqnum_t

Used for the number of messages in the message queue.

msglen_t

Used for the number of bytes allowed in a message queue.

These types shall be unsigned integer types that are able to store values at least as large as a type unsigned short.

The <sys/msg.h> header shall define the following constant as a message operation flag:

MSG_NOERROR

No error if big message.

The msqid_ds structure shall contain the following members:

struct ipc_perm msg_perm Operation permission structure.
msgqnum_t msg_qnum Number of messages currently on queue.
msglen_t msg_qbytes Maximum number of bytes allowed on queue.
pid_t msg_lspid Process ID of last msgsnd
().
pid_t msg_lrpid Process ID of last msgrcv
().
time_t msg_stime Time of last msgsnd
().
time_t msg_rtime Time of last msgrcv
().
time_t msg_ctime Time of last change.

The pid_t, time_t, key_t, size_t, and ssize_t types shall be defined as described in <sys/types.h>.

The following shall be declared as functions and may also be defined as macros. Function prototypes shall be provided.